Chrysler Repair: 1996 3.8 town and country van, spark coils, coil pack

Question
im stuck can you please help me driving van and it just stopped running i have changed coil pack cam and crank sensor asd relays codes are coming up great has no fire can you tell me anything at all.also changed computer.

Answer
Hi Rose,
I just wanted to ask too if by "no fire" you meant no spark, or did you just mean it won't start and you don't know if it is an ignition or a fuel problem? If you don't know which it is, do you hear the fuel pump run for 1-2 seconds when you turn the key to run (but don't try to start it). If not, and you may need to position yourself outside the van just in front of the rear wheels to hear the fuel pump located in the gas tank, then listen again very closely to verify whether the pump is working. Another thing to do is check after trying to start it but to no avail if there is a smell of gas on a spark plug that you remove and inspect. Of course if you have a fuel gauge you can tap into the fuel rail at the test port to see if you are getting about 49psi when you crank the engine.
Just didn't want to leave any system "unturned" in the quest for why the no start. By "codes are coming up great" I assume you only get a 12 and a 55, or just a 55?
Roland




Hi Rose,
It appears that you changed over everything that could be faulty, so now we have to check the electrical functioning of the spark system. I understand you to say that you are not getting any spark at all 6 plugs. Did you test for spark with an insulated handle screwdriver inserted into each spark plug cap so as to touch the internal electrical wire at the far end, and then held with the metal screwdriver shaft 1/4" from the cylinder head while a helper cranked it over? I'll assume so. (If not tell me how you verified no spark.)
Then we have to determine whether you are getting 12V to the coil pack when you are cranking it and also whether the 3 'drivers' for the 3 spark coils are working. If you remove the plug-in for the coil pack you will see four contacts. If you hold the plug so the locking tab is down (and the indentation is thus to the left) then the 12V primary supply voltage for the coils will be present on the upper right contact. While cranking the engine see if in fact you get a steady 12V on that contact, using a voltmeter or neon glow lamp with one lead on ground (any metal surface of the engine) and the other lead on the upper right contact. If that is present then it proves that the crank sensors, ASD and computer are o.k. as far as power to run the coil pack is concerned.
Then use the voltmeter or glow lamp to test if the other three contacts of the coil pack plug are each being momentarily grounded when you crank the engine, in synchrony with the speed of rotation (each should be grounded once for every two revolutions of the engine, so if the starter is cranking at 350 rpm the glow light should pulse about 3 times per second). Put one wire of the glow lamp on the + post of the battery for a voltage source and the other wire should be used to test each of the other three contacts of the plug: the upper and lower left and the lower right contact (you could also use an ohmmeter with one lead placed at each of the three contacts (one at a time) and the other lead touching a metal ground point and then observe whether its ohm reading pulses 3 time per second or so when you crank the engine. This may be hard to detect with a digital meter so the glow light may be a better testor. An old-fashioned analog ohmmeter type would work better). If that pulsing is happening then you will have proven that the primary control circuits for the coil pack are working properly. At that point, if the spark wires are good you should get spark at all 6 plugs. You could remove a plug and with the spark cap replugged into it and then while holding the plug with its threads touching a metal surface of the engine you ought to see spark jumping across its electrodes when you crank the engine. So try all those tests and let me know which if any fail and we can get to the bottom of this problem.
Roland